Finding the Fourth Proportional to 1,128.81, 1,558.50 and 709.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.81 : 1,558.50 = 709.62 : x
2. Step 2: Convert to fraction form
   1,128.81/1,558.50 = 709.62/x
3. Step 3: Cross multiply
   1,128.81x = 1,558.50 × 709.62
4. Step 4: Simplify right side
   1,128.81x = 1,105,942.77
5. Step 5: Solve for x
   x = 1,105,942.77/1,128.81
6. Step 6: Final answer
   x = 979.74